Shock-absorbing mount



sept. 17, 1935.

111/1/11111/111'II/llll/IIILz 'll/Ill L. D. NORTON SHOCK ABSORBINGMOUNTFiled Dec. 6, 1932 11,111 1,111,111,111,filiaal/111,1111,111.

ATTORNEYS Patented 'Sept'. 17, 1,935

UNITED STATES` lPATENT vorrlcle:

v 2,014,581 snoek-ABSORBING MoUN'r Leland D.Norton, Bridgeport, Conn.,assigner to Dictaphone Corporation, New York, N. Y.,l a

corporation of New York Application December 6, 1932, Serial No. 645,878

2 Claims.

y from other ofcedevices such as typewriters or f padding machines. Thisis -especially desirable the caseof reproducing machines used for thetranscription of dictation records. Where it has been attempted to mountreproducing-machines directly upon a typewriter desk lit has been foundthat the shocks and vibrations set up in operating the typewriter havebeen transmitted to the reproducing machine in such manner as to causeindistinct and distorted reproduction and loud unpleasant noises. Thisresult arises not only by reason of the operation of the keys of thetypewriter but also and particularly when the carriage of the typewriteris reversed or thrown back to its right-hand position.`

In reproducing mechines it isnecessary not only that the stylusImounting has freedom 0f movementvin an up-'and-down direction in orderthat the stylus may follow a hill-and-dale record and to compensate forvariations in the` cylindrical contour of the record, but also that thestylus be mounted for freedom movement in a lateral or horizontal planein order that the stylus may track the record. Therefore, since thestylus mounting permits freedom of movement of the stylus in bothvertical and horizontal planes, the stylus is especially responsive tocomponents 'of shocks or vibrations in those two planes. Vibrations orshocks in the vertical plane Amay cause the stylus to jump up and down,thus 40 skipping or rendering indistinct parts of the record, whilelateral shocks such as that caused by the throwing ofthetypewritercarriage from one position to the other may have two evileffects'. One of theseis due to the fact that the needle may be causedto shift from side to side in the record groove and thus not followeffectively the portion of the groove where: the record is mostdistinct. The other effect results from shocks so severe as to cause theneedle to jump from one groove to another, thus causing` repeti tion oromission of a part of the record.

As stated above, these effects are more pronoun'ed with the reproducingmachine. However, in the employment of. recording machines where thestylus is mounted for freedom of movement in a vertical plane andordinarily not 'in a horizontal plane, it is also necessary to mount themachine in such a way as to damp out vibrations and shocks to thehighest possible degree and this is particularly necessary in caseswhere 5 the machines are used upon moving trains or in automobiles.

One of the objects of this invention is to provide a simple andeiiicient mounting ofv the character described. Another object is toprovide a 10 shock-absorbing mount for phonographic reproducing machinesadapted effectively' to absorb those vibrations which tend mostpowerfully to interfere with the emcient operation of the machine. 15

Other objects will be in part obvious and in part pointed outhereinafter.

The invention accordingly cons1sts in the features of construction,Acombinations of elements, and arrangements of parts as willbe exemplied20 in the structure to be hereinafter described and the scope of theapplication of whichv will be indicated in the following claims.

In the. accompanying drawing in which lis shown one of thevariouspossible embodiments 25 of my invention: f

Fig. 1 is a perspective view of my shock-absorbing mount showing inphantom outline a reproducing machine mounted thereon;

Fig. 2 is a cross-section of the shock-absorb- 30 ing mount taken online 2-2 of Fig.' 1;

Fig. 3 is a cross-section of the mount taken on line 3--3 of Fig. 2; and

Fig. 4 is a cross-section through the sound-box of a well-known type ofreproducing machine 35 showing the mounting of the reproducing stylus.

Similar reference characters refer to similar parts throughout thevarious views of the drawmg.v

In Fig. 1 the ghost outline of the reproducing 40 machineshows it asseated upon a platform Ill which is mounted for free horizontal movementby means of suspension members, indicated generally by the numeral II,which are supported at their upper ends by members I2 formed integral-45 ly with or attached to a base plate I3. As shown in Fig. 2 pads I4 offelt or the like are attached by means of an adhesive to the undersideof the base plate and a cover I5 of billiard cloth or other suitablematerial is also shown as secured to the 50 underside of the base plateto cover the felt pads I4 andthe otherwise exposed portions of the base.plate. There are four of the brackets I2, each secured to the base plateadjacent a corner thereof and having anupwardly extending -por- 55 Aentinvention provides a lmeans for tion I 6 the height of which above thebase plate will be determined by the conditions arising from the designof Athe machine which the shock-absorbing mount is intended to support,as will be more fully explained hereinafter.

At the upper end of each upright I6 is a threaded hole I'I adapted toreceive a screw I8 which pivotally supports an eyeletmember I9. Thesuspension member II is composed of two distinct elements, one aninextensible cord or link 20 and the other a stiiily resilient helicalspring 2I. The link 20 is made preferably of a length of stranded wirecord which is soldered or otherwise secured at its upper end to theeyelet I9' and which at its lower end is soldered or otherwise securedto an eyelet 22. Eyelet 22 receives and supports an end of helicalspring 2|, the'other end of which passes throughan opening 23 in anupturnedY lug or ear formed at one end of a metal strip -36 'secured tothe underside of vthe platform IIUy adjacent and parallel to one end ofsaid platform A similar lug at the other end of said strip cooperateswith a second suspension member; and a like strip similarlyplaced.

at the other end of said platform is engaged at its two ends by twoother suspension members. Thus four-point suspension is provided. -Itwill be noted that' because of the lateral angularity of the suspensionmembers the platform will have less freedom of movement laterally thanlongitudinally.

The phonograph shown in Fig. 1 comprises a sound-box 24 supporting areproducing stylus 25 adapted to track and reproduce the record formedupon a cylinder 26. Referring to Fig. 4 it will be seen that the stylus25 is carried by a lever 2l pivoted at 28 to a weight lever "29, thestylus lever 21 being connected at its end opposite the stylus 25 bymeans of a link 30 with the soundbox diaphragm 3l. Thus the stylus isadapted to move up and down about the horizontal pivot 28. The weightlever 29 is also mounted upon a horizontal pivot 32 for movement in anup-and-down direction. The pivot 32 is supported in a member 33supported in the sound-box by means of a vertical pivot member 34. Inthe operation of va reproducing machine the weight lever 29 may be.raised or lowered about its pivot 32 in order to permit the stylus torest upon the record or be lifted therefrom. In its lowered position, asshown in Fig. 4, the stylus will be in contact with the record and willmove with the carriage of the reproducing machine from end to end of therecord and reproduce the dictation recorded thereon. The freedom ofmovement of the stylus lever 21 about its pivot 28 permits the stylus tofollow the up-and-down irregularities of the record groove while thelateral freedom of movement of the weight' lever 29 about its verticalpivot 34 permits a freedom of movement of the stylus from side to sidein order that it may -follow the track of the record.

It will be understood that these parts of the sound-box,

mounting, including the stylus lever and the weight lever, have a.natural period of vibration with respect to the pivot 34 and that thestylus weight 29 has a natural period of vibration about the pivot 32.It has been found that unless these natural periods of vibration aretaken into consideration in designing a "shock-'absorbing mount, it isimpossible to secure uniformly eilicient results in the use of themount. The presabsorbing vibrations acting either horizontally orvertically,l

namely, the entire movable stylusL element having elasticity or 4stylusmounting responsive to horizontal' components of shocks or vibrations,namely, the weight pivoting upon the pivot 34, it has been founddesirable to give the shock-absorbing mount freedom of movement in ahorizontal plane by a suspension means having a natural period ofvibration of a lower frequency than the 10. said natural period ofvibration of the stylus mounting about its said vertical pivot 34.v Thisis accomplished by providing that the suspension members I I as a wholefrom their pivotal attachment points at I8 to their attachment 15 pointsat 23 be of such length that tha natural period of vibration about thepivots I8 of the platform II) is lower than the natural periodl ofvibrationof the stylus mounting about the pivot 34. It will beunderstood that the link 23 may 20 be a rigid link having universalmovement at I8 or, as is preferable, a flexible cord such as has beendescribed above, pivotally mounted at I B for movement in a singleplane. Its flexibility permits it to swing in atransverse plane so as to25 permit movement of the supporting platform I0 either longitudinallyor transversely of the base plate I3. It will be further understood thatin selecting the length of the suspension members, it is desirable toemploy such lengths that not 30 only will the natural period ofvibration of the pension members it has been found most practical and*eflective4 to use short, fairly stiil" springs in order that theirnatural period of vibration will45 be of a higher degree than thenatural period of vibration of the stylus weight about its horizontalaxis. Such springs will not transmit easily to the stylusvibrationshaving the same frequency as4 the natural period of Avibrationof the stylus 50 mounting. Therefore, shocks having vertical componentsof a periodicity similar to that of the stylus mounting will be absorbedand rendered harmless to produce bad effects upon the stylus action. y55 As lstated above, while the shock-absorbing mount is herein disclosedin connection with a transcribing machine, it is equally effective whenused with a dictation machine, only it should be' understood that thenon-resilient and resilient 60 portions of the suspension members shouldbe proportioned with direct reference to the natural periodicity of'vibration of the stylus mounting. Therefore, although the proportions ofthe parts may be varied, it will be understood thatbest 65 results willbe obtained by employing a suspension 'member as herein disclosedcomprising a flexible inelastic or non-resilient element whichl isadapted to swing in any direction and a'.l resilient resiliency in thedirection of the pull of the support. l

While I have shown the underside of the base plate as being covered witha fabric covering and supported by means of shock-absorbing pads I4,

'these pads are not essential to the satisfactory 75 operation of thedevice but merely serve to prothe metal of the base plate and facilitatesliding the mount from one place to another upon the desk. Of course thefelt pads Il do to some extent act as shock absorbers but this is nottheir primary purpose. A handle 35 is secured to the base plate, asillustrated in Fig. 1, in order that the shock-absorbing mount with itssupported machine may be more readily moved from one position toanother.v

It will thus be seenthat this invention provides a construction of anessentially practical nature, in which the several objects of theinvention are attained. f

As many possible embodiments may be made oil the above invention withoutdeparting from the scope thereof, it is to be lunderstood, that allmatter herein set forth or shown in the accompanyi'ng drawing is to beinterpreted as illustrative and not in a limiting sense. y

I claim as my invention:

1. In a shock-absorbing mount for dictating machines provided with asound translation device comprising elements having a natural period ofvibration of a certain order in relation to a vertical axis and anatural period of vibration of a different order in relation to ahorizontal axis, suspension means comprising a' machine supportf ingplatform suspended by a plurality of swingable suspension members, eachof said suspension members being of a length to cause its natural periodof swinging movement to be of a substantially diEerent order than thesaid natural period of said translation device elements in relation totheir vertical axis, and resilient means iorming a component of eachsaid suspension member and having a natural period of vibration of asubstan- 5 tially diierent order than the said natural period of saidelements in relation to their horizontal axis, whereby sympatheticvibration of said elements in response to both horizontal and verticalshock components is prevented. 2. In a shock-absorbing mount fordictating machines provided with a sound translation device comprisingelements having a natural period of vibration of a certain order inrelation to a vertical axis and a natural period of vibration of adifferent order in relation to a horizontal axis, suspension meanscomprising a, machine supporting platform suspended y a plurality ofswingable suspension members, each of said suspension members being of alength to cause its natural period of swingimg movement to be of asubstantially lower order than the said natural period of saidtranslation device elements in relation to their vertical axis, andresilient means forming a component of each said suspension member andhaving a natural period of vibration of a substantially higher orderthan the said natural period of said elements in relation to theirhorizontal axis, whereby sympathetic vibration of said elements inresponse to bothA horizontal and vertical shock components is prevented.

' LELAND D. NORTON.

